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Arctic warming causes concern among scientists

While Europe freezes, the polar region continues to see unprecedented warm weather.

28 Feb 2018 10:06 GMT

Most of the coverage of Europe's weather over the last week or so has been, rightly, focused on the so-called, 'Beast from the East' and the Sudden Stratospheric Warming' (SSW).

Both SSW and the intense anticyclone that caused frigid Siberian air to sweep across Europe are entirely natural events, albeit quite infrequent. The same cannot be said for some of the weather anomalies being reported in the Arctic region.

Scientists understanding of the polar regions, in general, is limited. An accurate database of instrument readings extends back just a few decades, and reliable satellite data from the region only became available in the 1970s.

Nevertheless, many climate scientists are concerned about the extent of the recent warming in the region, which appears to be accelerating at a dramatic rate.

In the last week, temperatures have reached above freezing (0 degrees Celsius) at the North Pole.

It is important to remember, that the region is in the depths of winter, with almost total darkness.

Even more remarkably, the weather station on the northern tip of Greenland, Cape Morris Jesup, recorded a temperature of 6.1C on Sunday, and temperatures remained above freezing there for 61 hours, a new record.

This month there have been 10 days above freezing for at least part of the day at this weather station, which lies just 700km from the North Pole.

According to Ruth Mottram of the Danish Meteorological Institute, "spikes in temperature are part of the normal weather patterns - what has been unusual about this event is that it has persisted for so long and that it has been so warm."

She added: "Going back to the late 1950s at least, we have never seen such high temperatures in the high Arctic."

Speaking to Live Science, James Overland, an oceanographer with Pacific Marine Environmental Laboratory said: "We've seen something like this once every 10 years in the past, but this is the second major example of this happening in the last couple of years. What's different this time is that we have less ice and thinner ice in the Arctic. When you bring warmer air north, it doesn't cool off as fast as it used to.

All this is hardly surprising as 2015, 2016 and 2017 are the three warmest years globally since records began in 1880. The Arctic region is warming at a much greater rate than anywhere else. Globally, temperatures have risen by about 1C in the last 100 years, but in the Arctic region, the warming is closer to 3C.

This has resulted in a sustained year-on-year decrease in the extent of sea ice, and what coverage there is, is of much thinner, younger ice than in the past.

Climate scientists disagree as to the extent to which the current warming is directly attributable to human-induced climate change.

"The current excursions of 20C or more above average experienced in the Arctic are almost certainly mostly due to natural variability. While they have been boosted by the underlying warming trend, we don't have any strong evidence that the factors driving short-term Arctic variability will increase in a warming world," he said

But Michael Mann, director of the Earth System Science Center at Pennsylvania State University, takes a different view.

"This is an anomaly among anomalies," Mann said.

"It is far enough outside the historical range that it is worrying - it is a suggestion that there are further surprises in store as we continue to poke the angry beast that is our climate," he added.

"The Arctic has always been regarded as a bellwether because of the vicious circle that amplifies human-caused warming in that particular region. And it is sending out a clear warning."

What is clear is that the weakening of the polar vortex, because of the warming in the region, makes the climate more unstable. This encourages longwave ridges and troughs to develop in the flow around the Arctic Circle.

Plunges of cold air across Europe and domes of warm air across the Arctic could become more frequent events in the years ahead.